Detection of Toxoplasma gondii specific antibodies in dogs: a comparative study of immunoenzymatic, immunofluorescent and haemagglutination titers

RESUMO

We evaluated the titers os anti-T. gondii antibodies by various serological testes in 40 serum samples from dogs exhibiting clinical signs of infectios diseases. Indirect immunoflurescence (IgG-IFI), indirect haemagglutination (IHA and M-Toxo) and immunoenzymatic (ELISA and PA-ELISA) tests were carried out. Titers > 64 were considered as positive. Anti-Toxoplasma antibodies were found in 9 (22.5 per cent), 14 (35 per cent) and 12 (30 per cent) samples, respectively for IHA, IgG-IFI, ELISA and PA-ELISA. The results showed that 57 per cent were negative in all tests and 43 per cent of the dogs presented antibodies to T. gondii; from these, 20 per cent were positive in all three tests with high titers of antibodies and 23 per cent were positive in only one or two tests with low titers of antibodies and mainly related to the IFI and ELISA tests. We observed 5 (12.5 per cent) and 1 (2.5 per cent) reactive samples, respectively, by M-Toxo and IHA with or wihout 2-mercapthoethanol, in the attempt to detect specific IgM. We can conclude that serodiagnosis of toxoplasmosis in dog have to be based on the combination of serological tests (IFI and ELISA) and with emphasis at the determination of the titers and the classes of specific antibodies.